Injector test machine

ABSTRACT

A fuel injector test machine is provided such that an injector is fixed on a test feature with a manually operable clamp.

CROSS REFERENCE TO RELATED APPLICATIONS

This application is a national stage application under 35 USC 371 of PCTApplication No. PCT/EP2018/078097 having an international filing date ofOct. 15, 2018, which is designated in the United States and whichclaimed the benefit of GB Patent Application No. 1717027.5 filed on Oct.17, 2017, the entire disclosures of each are hereby incorporated byreference in their entirety.

TECHNICAL FIELD

The present invention relates to a fuel injector test machine.

BACKGROUND OF THE INVENTION

Certain diesel injectors are fitted to a range of medium duty passengervehicle and off-highway applications. Said injectors use an intensifiersystem to amplify engine oil pressure between 30-300 bar to generatehigh injection pressure, 300-2000 bar, for EN590 diesel fuel which isutilized to combustion.

The injector is clamped into the engine using dedicated mounts andremoval requires dedicated tooling to support removal of the injectorwithout causing damage due to the tight O-ring squeezes for thehydraulic connection.

During service operations, the injectors are removed from the engine andclamped on a test machine for measuring actual performances such asmeasurement of injected delivery, measurement of the electrical coil(resistance/inductance) or measurement of injection timing from start ofelectrical pulse to injection event. Said performance tests enable toproperly diagnose the injectors but, service test machines are complexequipment's requiring specific tooling to arrange the injector on thetest bed, with similar risk of damaging the injector. Therefore, testingtime is long to set up and, at completion a similar long time is neededto remove the injector from the machine. A more simple machine, easierto use is required.

SUMMARY OF THE INVENTION

Accordingly, it is an object of the present invention to resolve theabove mentioned problems in providing a test machine adapted to executehigh pressure fuel injector tests on several types of fuel injector.Each of said injector has an injector body extending along alongitudinal axis from a head to a spray nozzle tip, the head beingprovided with an electric connector for transmitting command signals toan actuator cooperating with a valve member controlling injection spraythrough said tip.

The test machine defines a test chamber wherein the injector can befixed on a test feature by means of manually operable clamps.

Said manually operable clamps may comprise latch toogle clamps, each ofthe toogle clamps comprising a handle articulated about a fixationmember for stretching a resilient ring, said fixation member being fixedto the test feature.

Also, for fixing the injector said resilient ring is engaged in a hookarranged on the injector head, said hook being part to a test head caparranged over the injector head or directly bolted to the injector.

The test feature may comprises a base member on which is arranged aninterface member, said base member being attached to the machine andbeing common to all types of injectors and, the interface members beingspecifically designed for a particular type of injector, to each type ofinjector corresponding a dedicated interface members.

The interface member may be a sleeve provided with a through boreadapted to receive the nozzle of the injector wherein it is sealinglyinserted, the head of the injector protruding outside the sleeve, saidsleeve being provided with drillings for inter-connecting a machine highpressure fuel inlet to the injector fuel inlet.

In another aspect of the invention, the test feature is adapted to movebetween a mounting position and a test position, the mounting positionbeing suitable for arranging the injector on said test feature and, thetest position being suitable for testing said injector.

In said test position the longitudinal axis of the injector issubstantially parallel to the front wall opening access and in saidmounting position, the test feature is tilted toward the opening accessto ease the injector arrangement on the test feature.

In said mounting position the longitudinal axis of an injector arrangedin the interface member extends through the front wall opening access,or at least in the direction of it.

In an aspect of the invention, the sleeve may be fixed to the basemember, the base member being moveable relative to the machine housing.

In another aspect of the invention, the base member is fixed relative tothe machine housing and the sleeve is moveable relative to the basemember between the mounting position and the test position.

The test machine may further comprise an electronic command unit in amemory of which the tests method executable by the machine are uploaded.

The test machine may further comprise a display connected to saidcommand unit for an operator to select a particular test.

In a particular aspect of the invention, the test machine has asubstantially parallelepiped body enclosing said test chamber, said bodyhaving a front wall provided with said access opening and, the displayis arranged on the front wall above the access opening.

The invention further extends to a method for arranging an injector on atest machine described above, said method comprising the steps of:

-   -   providing an injector to be tested;    -   providing a sleeve adapted to the injector of step;    -   tilting the base member to the mounting position;    -   clamping said sleeve on the base member;    -   inserting the injector chosen at step into the sleeve;    -   rigidly fixing said injector by downwardly pulling the handles        of the latch toggle clamps;    -   tilting the base member back to the test position;    -   locking the base member into said test position;    -   closing the access opening by means of a door;    -   selecting on the display the type of injector to be tested;    -   selecting on the display the test to be executed.

The invention further extends to a method for removing an injector froma test machine after having performed a test, said method comprising thesteps of:

-   -   accessing the injector that has been tested and, unlocking and        tilting the base member to the mounting position;    -   releasing the latch toggle clamps by upwardly pulling the        handles of said latch toggle clamps;    -   removing the injector from the sleeve.

BRIEF DESCRIPTION OF THE DRAWINGS

The present invention is now described by way of example with referenceto the accompanying drawings in which:

FIG. 1 is a side feed injector to be tested on a test machine of FIG. 2.

FIG. 2 is an 3D view from the test machine as per the invention.

FIGS. 3 and 4 are sketches representing an operator using the machine ofFIG. 1.

FIG. 5 shows the injector of FIG. 1 arranged in the machine of FIG. 2 ina mounting position such as sketch in FIG. 3.

FIG. 6 shows the injector of FIG. 1 arranged in the machine of FIG. 2 ina test position such as sketch in FIG. 4.

FIGS. 7 and 8 detail the test feature of the machine of FIG. 2.

FIG. 9 shows a base member of the test feature.

FIGS. 10, 11 and 12 detail an interface member also part of the testfeature.

FIG. 13 is an exploded view of a head cap part of the test feature.

FIG. 14 is a 3D view of the injector fixed in the test feature.

FIGS. 15, 16 and 17 detail the sequence of operations for mounting theinjector onto the mounting feature.

FIGS. 18, 19 and 20 detail the sequence of operations for disassemblethe injector from the mounting feature.

DESCRIPTION OF THE PREFERRED EMBODIMENTS

In reference to FIG. 1 is briefly presented a diesel fuel injector 10adapted to be part of a fuel injection equipment of an internalcombustion engine. The injector 10 has an elongated shape extendingalong a longitudinal axis X and it comprise an injection nozzle 12 overwhich, by means of an injector capnut, an actuator assembly 14 is fixed.

In use, the injector 10 is placed in a well provided on the enginecylinder head, the bottom end of the well opening into a compressionchamber. The head end 16 of the injector, where is arranged an electricconnector 18 internally connected to an electrovalve, protrudes outsidethe well and, at the opposite end the tip 20 of the injection nozzleprotrudes through said bottom opening for spraying pressurised fuel intosaid compression chamber.

The fuel injector 10 shown on FIG. 1 is a side feed injector 10S havingan engine oil gallery 24O and a diesel fuel inlet 24S sealinglyseparated by O-rings? The gallery 24O forms an annular groove around theinjector and, the fuel inlet 24S opens laterally on the outer face ofthe injector. In a fuel injection equipment provided with such side feedinjectors 10S, engine oil flows toward the injector in the gallery 24Oand, diesel fuel enters the injector via said inlet 24S.

Another embodiment of injector 10 is a top feed injector 10T (shown onFIG. 13) having a fuel inlet 24T arranged atop the injector head.

During life of the injector 10 service may be needed requiring testsand, diagnosis is made in a test machine 30 as generally presented inFIG. 2. Typical tests performed are performance tests involving forinstance a measure of current needed to spray high pressure fuel or, ameasure of a fuel quantity sprayed in a certain time duration.

The test machine 30 is designed to test several types of injectors 10all having a similar configuration, as described above, but differingfrom one another by their actual dimensions, length, diameters . . . .

Said machine 30, designed to be placed on a table, has a substantiallyparallelepiped body with six lateral walls 32 enclosing a test chamber34 wherein is a fixed frame to which is attached a test feature 44adapted to receive a fuel injector 10. On the figure the most visiblevertical wall is the “front wall” 32F which in the lower part defines anforwardly advanced portion where control knobs are arranged orientedtoward an operator. This front wall 32F is also provided with arectangular access opening 36 enabling to enter and install the injectorin the test chamber 34, said opening being closed by a door 38 laterallyrotatable about a vertical axis. Above said opening 36, on the upperpart of the front wall 32F, are arranged a “touch-screen” digitaldisplay 40 and an emergency stop button 42. A command unit 43 controlsthe machine as per inputs on said digital display 40. Said front wallarrangement is an example and is presented without intent to limit theapplication. In alternative embodiments, the knobs and the commanddisplay can be differently arranged otherwise on the wall or can beplaced on a separate console connected to the machine.

As sketched on FIGS. 3 and 4, an operator can easily arrange an injector10 in the test chamber 34 by engaging it through the opening 36 and thenafter closing the door 38, he/she selects on the display 40 the test tobe executed.

In the test chamber 34, the injector 10 is arranged on said test feature44 that can be moved between a mounting position PM (FIGS. 3 and 5) and,a test position PT (FIGS. 4 and 6). On the example presented, to movebetween said positions PM, PT the test feature is angularly tilted aboutan horizontal axis. Alternatively, other arrangements can be made forinstance having said test feature translated toward the access opening36 for easing the injector arrangement.

In the test position PT the injector is fixed in said test feature 44 sothe injector longitudinal axis X is parallel to the front wall 32F and,a lock 45 locks the test feature 44 to the frame, the test feature notbeing able to move during the performance of a test.

The lock 45 comprises a male member integral to the test feature 44 andcomplementary engage-able in an adjusted female member integral to theframe and, a locking bolt that can be inserted in a bore drilled forpart in the male member and for a other part in the body of the femalemember. In test position PT, the two parts of the bore are aligned andthe locking bolt is engaged therein. Alternatively, many other lockingmechanism can be provided.

In the mounting position PM the test feature is unlocked and isangularly pivoted toward the access opening 36 so the injector placed inthe test feature 44 has its longitudinal axis X extending through, or atleast in the direction of, said access opening 36. Consequently, settingthe injector in the feature 44 is made easy.

More particularly in reference to FIGS. 7 and 8, said test feature 44comprises a base member 46 and an interface member 48. The base member46 is fixed to the frame at it defines a bottom side 46B wherein ishydraulically connected a high pressure fuel pipe 50 and, a top side 46Tadapted to receive said interface member 48. The base member 46 isfurther provided with channels 51 enabling HP fuel to flow out of thepipe 50 into said channels 51, here after described, arranged in thesleeve 48.

The interface member 48 of the present example is a sleeve 48 having atubular body with an upper end 48U and a lower end 48L for complementaryarrangement on the base member 46. Said sleeve 48 defines an axialthrough bore 52 surrounded by a thick peripheral wall 54 in whichretention notches 56 are provided at the lower end 48L of the outerface. Said notches 56 enable to rigidly fixe the sleeve 48 to the basemember 46 by means of two clamping plates 58 screwed in the base membertop side 46T and engaged in said notches 56. Alternatively an annulargroove could be provided replacing said notches and forming a shoulderfor the clamps abutment. The injector 10 is inserted in the bore 52 andit is fixed in position by means of two latch toogle clamps 60themselves fixed on the sleeve 48.

In reference to the FIG. 9 is presented the top side 46 T of the basemember defining a recess 62 for positioning the sleeve 48 and said twoclamps 58 diametrically opposed. In said recess 62 a central hole 64enables the nozzle tip 20 to extend through and, around said centralhole 64 protrude HP fuel connections.

The sleeve 48, presented on 3D FIG. 10 shows the outer face of the wall54 with the clamping notches 56 (only one being visible) and apositioning slot 66F for complementary engagement of pins 66M extendingfrom the base member on the outer border of the recess 62. Also, saidouter face is provided with flats 68 for screwing said toogle clamps 60on the upper end 48U of the sleeve.

FIGS. 11 and 12 are axial sections of a sleeve specially designed for aside feed injector 10S, said sections being 90° apart from one another.In the thickness of the wall 54 are drilled the vertical channels 51,comprising an oil channel 51O for the engine oil and, two diesel fuelchannels 51D (feed and return). Said drillings upwardly extend from anopening in the under face 49 of the sleeve (visible on FIG. 10) toannular gallery in fluid connection with, the oil gallery 24O of thediesel fuel inlet 24S.

For top feed injectors, the sleeve 48, not shown in section, does notneed said drillings 51.

The machine 30 has a unique base member 46 attached to the machine andcommon to all different types of injectors 10, 10S, 10T and, a pluralityof sleeves 48, each being specifically made to a specific type ofinjector 10, 10S, 10T. The sleeve 48 is the interface member between astandard base member 46 and a particular injector 10.

All the sleeves 48 have the same characteristics of through bore 52,notches 56 on the outer face of the wall and flats 68 for fixing toogleclamps 60.

In reference to FIG. 13, to maintain the injector 10 in the sleeve 48 (atop feed injector 10T is shown on FIG. 13) a U-shaped member 72 iscomplementary engaged in clamp grooves of the injector head 16, each armof said U-shaped member 72 being provided with a hook 74. Also shown onsaid figure, an inlet block 75 is screwed atop said injector 10T toenable fuel inlet into the top feed injector 10T.

The toogle clamps 60 have a handle and a resilient ring both articulatedabout a fixation member fixed to the sleeve 48. For fixing the injector10 each resilient ring is engaged in one of the hooks 74 and, bydownwardly pulling the handles, the resilient rings are stretched urgingand fixing the injector in the sleeve as presented on FIG. 14. In theexample said rings have an elongated rectangular shape althoughalternatives exist.

Thanks to this arrangement an operator can easily set an injector in themachine, this operation being done manually just by pulling the handlesof the toogle clamps without any needs for tools. The forces generatedby the toogle clamps 60, once stretched by the handles, are sufficientto maintain the injector in place and, a test using a fuel flow forinstance at 300 bars can be performed. This assembly of an injector onthe test machine is illustrated by the sequence represented on FIGS.15-17, the arrows indicating the direction of insertion of the injectorin the sleeve, the direction for engaging the rectangular rings in thehooks and the direction of pulling the handles. The opposite operationof disassembling said injector is shown on the FIGS. 18-20.

In the embodiment presented the sleeve 48 is fixed to the base member 46and the base member 46 is articulated about the main frame. In anotherembodiment not shown, the base member 46 may be fixed relative to theframe and, the sleeve 48 may be provided with a device to enable tiltingof the sleeve relative to the base member.

To run the machine, an operator arranges the injector in the machinethen he/she selects the test to be performed on the digital display 40.By selecting a particular test and a specific injector 10 a set of inputsignals is sent to the command unit 43 wherein in a memory all the testprocedures are stored and all the different type of injectors that canbe tested on said machine.

Setting an injector on the machine for performing a test involvesrunning the following method 100 steps:

102) providing an injector 10 to be tested;104) providing the sleeve 48 adapted to the injector provided;106) tilting the base member 46 to the mounting position PM;108) clamping said sleeve 48 on the base member;110) inserting the injector chosen at step 102) into the sleeve;112) rigidly fixing said injector by downwardly pulling the handles ofthe latch toggle clamps 60;114) tilting the base member 46 back to the test position PT;116) locking the base member 46 into said test position PT;118) closing the door 38 of the access opening 36;120) selecting on the digital display 40 the type of injector to betested;122) selecting on the digital display 40 the test to be executed.

When the test is completed the injector 10 is removed from the machine30 in following the steps of the following method 140:

142) accessing the injector 10 that has been tested and tilting the basemember 46 to the mounting position PM;144) releasing the latch toggle clamps 60 by upwardly pulling thehandles of said latch toggle clamps;146) removing the injector 30 from the sleeve 48.

LIST OF REFERENCES

-   -   X longitudinal axis    -   PM mounting position    -   PT test position    -   10 fuel injector    -   10S side feed fuel injector    -   10T top feed fuel injector    -   12 nozzle    -   14 actuator assembly    -   16 head end of the injector    -   18 connector    -   20 tip end of the nozzle    -   22 injection holes    -   24O Engine oil gallery    -   24S side feed injector diesel fuel inlet    -   24T top feed injector diesel fuel inlet    -   30 test machine    -   32 walls    -   32F front wall    -   34 test chamber    -   36 access opening    -   38 door    -   40 display    -   42 emergency stop button    -   43 command unit    -   44 test feature    -   45 lock    -   46 base member    -   46B bottom side of the base    -   46T top side of the base    -   48 interface member—sleeve    -   48U upper end of the sleeve    -   48L lower end of the sleeve    -   49 under face of the sleeve    -   50 pipe    -   51 channels    -   51O oil channel    -   51D diesel fuel channels    -   52 bore    -   54 wall    -   56 notches    -   58 clamping plates    -   60 latch toogle clamps    -   62 recess    -   64 central opening    -   66F positioning slot    -   66M positioning pin    -   68 flat    -   72 U-shape member    -   74 hook    -   75 inlet block    -   100 method to perform a test    -   102 providing step    -   104 providing step    -   106 tilting step    -   108 clamping step    -   110 inserting step    -   112 fixing step    -   114 locking step    -   116 locking step    -   118 closing step    -   120 selecting step    -   122 selecting step    -   140 method to remove an injector after test completion    -   142 accessing step    -   144 releasing step    -   146 removing step

1-18. (canceled)
 19. A test machine adapted to perform high pressurefuel injector tests on several types of fuel injectors, any of saidseveral types of fuel injectors having an injector body extending alonga longitudinal axis from a head to a spray nozzle tip, the head beingprovided with an electric connector for transmitting command signals toan actuator cooperating with a valve member which controls spray throughholes provided in said spray nozzle tip, said test machine comprising: atest chamber, wherein any of said several types of fuel injectors can befixed on a test feature by means of manually operable clamps and whereinsaid manually operable clamps comprise latch toggle clamps.
 20. A testmachine as claimed in claim 19, wherein each of the toggle clampscomprise a handle articulated about a fixation member for stretching aresilient ring, said fixation member being fixed to the test feature.21. A test machine as claimed in claim 20, wherein said resilient ringis engaged in a hook arranged on the head.
 22. A test machine as claimedin claim 19, wherein said test feature comprises a base member on whichis arranged an interface member, said base member being attached to thetest machine and being common to all of said several types of fuelinjectors, and the interface member being specifically designed for aparticular one of said several types of fuel injectors.
 23. A testmachine as claimed in claim 22, wherein said interface member is asleeve provided with a through bore adapted to receive a nozzle of theinjector wherein it is sealingly inserted, the head of the fuel injectorprotruding outside the sleeve.
 24. A test machine as claimed in claim23, wherein the sleeve is further provided with drillings forinter-connecting a high pressure fuel inlet to an injector fuel inlet.25. A test machine as claimed in claim 22, wherein said test feature isadapted to move between a mounting position and a test position, themounting position being suitable for arranging the injector on said testfeature, and the test position being suitable for performing testing onsaid injector.
 26. A test machine as claimed in claim 25, wherein insaid test position the longitudinal axis is substantially parallel to anopening access provided to enable an injector to be entered andinstalled in said test chamber.
 27. A test machine as claimed in claim26, wherein in said mounting position, the test feature is tilted towardsaid opening access to ease installation of the injector on the testfeature.
 28. A test machine as claimed in claim 27, wherein in saidmounting position the longitudinal axis of the injector arranged in theinterface member extends through said opening access.
 29. A test machineas claimed in claim 23, wherein the base member is moveable relative tothe test machine and, the sleeve is fixed onto the base member.
 30. Atest machine as claimed in claim 23, wherein the base member is fixedrelative to the test machine and the sleeve is moveable relative to thebase.
 31. A test machine as claimed as in claim 19, further comprisingan electronic command unit in a memory of which test methods executableby the test machine are uploaded.
 32. A test machine as claimed in claim26, further comprising a display connected to said command unit for anoperator to select a particular test.
 33. A test machine as claimed inclaim 32, wherein the test machine has a substantially parallelepipedbody enclosing said test chamber, said body having a front wall providedwith said access opening.
 34. A test machine as claimed in claim 33,wherein said display is arranged on the front wall, above the accessopening.
 35. A method of using the test machine as claimed in claim 33,said method comprising the steps of: providing the injector to betested; providing the sleeve adapted to the injector; tilting the basemember to the mounting position; clamping said sleeve on the basemember; inserting the injector into the sleeve; rigidly fixing saidinjector by downwardly pulling the handles of the latch toggle clamps;tilting the base member back to the test position; locking the basemember into said test position; closing the access opening by means of adoor; selecting on the display the type of injector to be tested; andselecting on the display the test to be executed.
 36. The method ofclaim 35 further comprising the following steps after the steps of claim35: accessing the injector that has been tested and unlocking andtilting the base member to the mounting position; releasing the latchtoggle clamps by upwardly pulling the handles of said latch toggleclamps; and removing the injector from the sleeve.